1. Field of the Invention
The present invention relates generally to a vehicle mounted articlated boom apparatus and more particularly to an apparatus for vertical withdrawal of well pipe and other like objects. The vehicle being a mini truck which can also be used as a utility vehicle.
2. Description of the Prior Art
The present invention fills a long felt need for a compact, four wheel drive, self propelled vehicle having the capability to vertically withdraw well pipe and the like. Large rigs, which are currently used by the well and pump contractor, are often limited as to their accessibility to the work site. Structural obstacles such as trees, power lines, fences, swimming pools, valuable landscaping and other impediments, which in many cases did not even exist when the well was originally installed make the use of the large rig either very difficult or even impossible in many instances. Also quite often the terrain has changed due to erosion or other developments that make the large rig a potential hazzard. The combination of the heavy weight of the rig coupled with delicate soil conditions are other problems the contractor faces.
An unnecessary expense the well contractor has to absorb, is when two people have to be sent out on a job that requires only a single worker. This added cost must generally be passed on to the the consumer. The reason for this inefficiency is that on most jobs, the contractor needs to have a hoist truck for pulling the well pipe, and also a box or pick-up truck for carrying all the tools and parts to the job site. This requires two drivers, although only one is needed to perform the work. Thus, there is a need for a vehicle that will combine both the hoist and the extra truck, thereby eliminating one of the workers.
Some conventional solutions, which are available for pipe removal, often do not support the pipe for the full vertical extension from the ground. This can cause the pipe to bend or buckle under its own weight. A boom attachment is normally the best means to raise the pipe in a vertical and completely supported manner. One difficulty of the prior art apparatus, wherein booms are used, is that only the extremely heavy rigs will supportively lift the heaviest pipes up to at least 20 vertical feet. The booms must be articulated to each other and the requirement of outriggers is necessary to stabilize the vehicle. Overcoming this counterweight need has created numerous patents in the prior art. None of the prior art discloses a mini hoist, having the small structure of the present invention, yet still being able to support a vertical lift of more than 20 feet.
The prior art also presents many well known means for providing a high pressure, large hydraulic cylinder for raising and lowering boom members. The large cylinder has inherent disadvantages in that it must accommodate the lower boom when it is in the collapsed stage. Typically, the lower boom will have a U-shaped chassis, which allows the cylinder to be depose within the chassis of the boom when the hoist assembly is lowered. The disadvantage of the U-shaped chassis is that it must be larger, and therefore heavier, for any given load-bearing capacity. This is a very important consideration in striving for a small, light-weight apparatus.
U.S. Pat. No. 5,622,235 issued to Merritt on Apr. 22, 1997, shows a vehicle on tracks with hydraulically activated outriggers for support. Merritt has designed his vehicle to be accessible in such areas as residential back yards. The vehicle is small, maneuverable and self-propelled, however the boom arrangement is of a single boom with two distinct sections. This apparatus would not have the ability to supportively raise well pipe in a perpendicular direction
U.S. Pat. No. 4,925,159 issued to Younes on May 15, 1990, discloses a vehicle for pulling well points and the like utilizing a boom and outriggers. The size of his vehicle is about 6 feet by 11.5 feet. This is an improvement over the prior art but is still remains relatively heavy and could not be fit within a box truck. Younes' vehicle would also not supportively raise the pipe to any where near the minimum requirement of 20 feet.
U.S. Pat. No. 5,554,646 issued to Lewis et al. on Dec. 17, 1996, teaches the use of a mobile, self-propelled apparatus utilizing two boom sections actuated by hydraulic cylinder. As in most of the prior art, Lewis et al. does not show any means for pivoting the booms 180 degrees relative to each other.
U.S. Pat. No. 4,081,055 issued to Johnson on Mar. 28, 1978, illustrates a vehicle mounted actuated boom apparatus. Johnson teaches the coordination of actuated power cylinders, to allow perpendicularity while avoiding the inherent danger of instability caused by raising the boom too high.
U.S. Pat. Nos. 5,253,845 and 3,871,618 issued to Wilbert and Funk respectively, disclose devices that are small, very portable and teach the lifting of well pipe and pumps. These devices are quite commonly used in the water well industry, however they cannot support the pipe in the raised position, and therefore the pipe is often susceptible to bending or buckling.
None of the above noted patents, taken either singly or in combination, are seen to disclose the specific arrangement or concepts disclosed by the present invention.